In operating rooms at present, integration is the key to efficient surgical workflow. AV (Audio Visual) systems still in use in many operating rooms have limited integration possibilities, demand extensive cabling, and result in cluttered and complicated configurations. This complexity presents challenges in the surgical environment, where flexibility and scalability are critical to operational efficiency.
A fully IP-centric solution for image distribution in the operating room is now usually adopted in more recent ORs (Operating Rooms). In those ORs, the system architecture has been specifically designed to meet the performance demands and the unique requirements of the surgical suite, such as high-quality imaging, ultra-low latency, and real-time communication.
Examples of such networked based surgical systems or networked operating rooms are described in e.g. WO 2007/073420 “Streaming Video Network System” and EP 2081124A2 “Networked based endoscopic surgical system”.
When an operating room is installed, it usually integrates off-the-shelf equipment of the latest generation. For instance, around 2005, the format of images transferred over the network would have been Full HD (e.g. 1080p). In the example of FIG. 1, full HD cameras 2 and 4 would generate full HD images for a full HD display 7. AV-to-IP encoders 3 and 5 (like e.g. the MNA-120 supplied by Barco NV, Belgium) take in baseband video data and convert these to IP streams for transportation over a standard high bandwidth IP network 1. The decoder 6 reconverts these raw IP packets to DVI video signals for display on display 7. The IP streams can also be received by computers and/or servers like 8 for e.g. for archiving.
In some networked based solution like Nexxis™ from Barco NV, Belgium, a “management suite” on a computer 9 allows management and monitoring of the IP streams between the encoders and decoders, facilitating configuration and management Integrated within a user interface. The “management suite” software allows distribution of high quality video, audio, keyboard and mouse towards any destination with a single touch on the screen. For instance, the packets generated by the encoder 3 can be directed towards the decoder 6 in order to display the images captured by camera 2 on display 7 while the packets generated by encoder 5 are directed towards computer 8 for display and storage on that computer. This can be done with a user interface where it merely suffices to drag a source (icon associated with e.g. camera 2) and drop it on a sink (e.g. icon associated with display 7).
As the operating room is upgraded, new equipment can be added as illustrated on FIG. 2. The new equipment can be more advanced than the one originally installed. For instance the HD camera 4 of FIG. 1 can be replaced by a state of the art camera 10 capturing images of higher resolutions (e.g. a 4K camera). New displays like display 12 capable of displaying images at a higher resolution are connected to the network 1 to take advantage of the increased resolution of camera 10. 4K resolution, also called 4K, refers to a display device or content having horizontal resolution of the order of 4,000 pixels. Several 4K resolutions exist in the fields of digital television and digital cinematography. In the movie projection industry, Digital Cinema Initiatives (DCI) is the dominant 4K standard. The DCI 4K resolution standard is defined as 4096×2160 pixels (256:135, approximately a 1.9:1 aspect ratio).
If the 4K content generated by camera 10 is directed to HD display 7 problems may occur. Indeed, while a 4K display might be able to display HD content, an HD display having been manufactured without taking the existence of the 4K format into account might be incapable of displaying a 4K image at all.
One solution to avoid having to replace the encoders, decoders and/or displays of earlier generations when equipment designed to operate with images of a different format, is to let both image formats (HD/1080p and 4K in this example) coexist in one way or another. 1080p (also known as Full HD or FHD and BT.709) is a set of HDTV high-definition video modes characterized by 1080 horizontal lines of vertical resolution and progressive scan, as opposed to interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 1920×1080 (2.1 megapixel) and is often marketed as “Full HD”.
The drawback of that solution is that the amount of data to be streamed increases.
If HD-1080p images were originally streamed at a rate of 30 or 60 frames per second and without compression, it could be done with a single 10 Gb per second link.
If HD-1080p images are to be streamed at the same rate in parallel with 4K images without compression, two or more 10 Gb per second links are required.
In US20130314495 “Multi-layer backwards-compatible video delivery for enhanced dynamic range and enhanced resolution formats”, the two different formats (e.g. 4K and HD) are encoded together into a first and a second stream making use of base and enhanced layers. The first stream is sufficient to reconstruct the first format (e.g. HD) while the first and second streams are both used to reconstruct the second format (e.g. 4K). Use of base and enhanced layers in this way requires decoding and reconstruction to retrieve the original video signals. A possible issue with the technique disclosed in this document is the “lag” introduced by the decoding and reconstruction of the first and/or second format. Such a lag can be incompatible to allow proper eye to hand coordination if e.g. a surgeon is operating in remote (i.e. the patient and the surgeon are not at the same geographical location and a robot controlled by the surgeon is used).
Depending on the resolution and the frame rate of the images to be streamed, one may exceed the bandwidth of a single cable. For instance, the bandwidth required to stream the same images in 4K (8 million pixels) and HD (2 million pixels) formats is well above that of a single 10 GE cable (also known as 10 Gb Ethernet i.e. a cable whose bandwidth allows transmission of 10 gigabits per second).
A solution is required to allow the upgrade of existing network based display systems with as little modifications as possible. In particular a solution is required to allow transfer of higher resolution images using the existing network based display systems with as little modifications as possible.